Continuously variable transmission tap gear entry ratio selection during transient driving conditions

Abstract

A system of selecting a transmission manual mode entry gear during transient driving conditions of an automobile vehicle includes a transmission in an automobile vehicle. An engine is connected to the transmission. A torque converter is connected to the transmission, and a differential provides drive output. A controller is in communication with the engine and the transmission. A shift device is in communication with the controller allowing manual selection by an operator of the automobile vehicle between a Park, a Reverse, a Neutral, a Drive and a Low or Manual (PRNDL) operating modes. A predicted gear is frozen close to a real gear at a time of entrance into the Manual mode.

What is claimed is: 
     
       1. A system to select a transmission manual mode entry gear during transient driving conditions of an automobile vehicle, comprising:
 an automotive transmission; 
 an engine connected to the transmission, a torque converter connected to the transmission, and a differential providing drive output; 
 a controller in communication with the engine and the transmission; 
 a shift device in communication with the controller providing manual selection by an operator of the automobile vehicle between a Park mode, a Reverse mode, a Neutral mode, a Drive mode and a Manual mode; and 
 wherein at a time of entrance into the Manual mode a predicted gear is set to a bin center of an individual one of multiple bins adjacent to a real gear. 
 
     
     
       2. The system of  claim 1 , wherein the transmission defines a continuously variable transmission (CVT) having a first pulley connected to an input shaft and a second pulley rotatably driven by a belt displaceably connected to the first pulley and the second pulley. 
     
     
       3. The system of  claim 2 , further including a range of pulley ratios split into multiple bins independently defining successive segments of an overall range of ratios of the CVT. 
     
     
       4. The system of  claim 3 , wherein the predicted gear defines a predicted ratio and the real gear defines a CVT real ratio, and the predicted ratio set to the bin center of the individual one of the multiple bins adjacent to the real ratio at the time of entrance into the Manual mode includes the bin center of one bin to two bins removed from the real ratio at the time of entrance into the Manual mode. 
     
     
       5. The system of  claim 4 , further including an offset added to the CVT real ratio at the time of entrance into the Manual mode. 
     
     
       6. The system of  claim 5 , wherein the offset is based on a rate of change of the real ratio and retrieved from a memory in a calibratable lookup table. 
     
     
       7. The system of  claim 1 , wherein the transmission defines a planetary gear transmission having a sun gear, a ring gear and a carrier assembly. 
     
     
       8. The system of  claim 7 , further including a clutch and a brake which when selectively actuated provides for one of the Park mode, the Reverse mode, the Neutral mode, the Drive mode and the Manual mode, with the clutch also driving the differential. 
     
     
       9. The system of  claim 7 , wherein:
 the predicted gear is set to an entrance time into the Manual mode; and 
 an offset is added to the real gear, the offset based on a rate of change of the real gear. 
 
     
     
       10. A method of selecting a continuously variable transmission manual mode entry ratio during transient driving conditions of an automobile vehicle, comprising:
 providing a continuously variable transmission (CVT) connected to an engine; 
 controlling the engine and the CVT using a controller; 
 positioning a shift device in communication with the controller allowing selection by an operator of the automobile vehicle between a Park mode, a Reverse mode, a Neutral mode, a Drive mode and a Manual mode; 
 splitting a range of ratios of the CVT into multiple bins independently defining successive segments of the range of ratios; and 
 selecting a predicted ratio of the CVT at a time of entrance into the Manual mode at a center of one of the multiple bins adjacent to a CVT real ratio. 
 
     
     
       11. The method of  claim 10 , further including adding an offset to the CVT real ratio at the time of entrance into the Manual mode. 
     
     
       12. The method of  claim 11 , further including calculating the offset using a rate of change of the CVT real ratio. 
     
     
       13. The method of  claim 12 , further including retrieving the offset from a memory in a calibratable lookup table. 
     
     
       14. The method of  claim 10 , further including defining the center of one of the multiple bins close to the CVT real ratio as a bin center approximately one bin to two bins removed from the CVT real ratio at the time of entrance into the Manual mode. 
     
     
       15. The method of  claim 10 , further including connecting a first pulley to an input shaft and rotatably driving a second pulley by a belt displaceably connected to the first pulley and the second pulley. 
     
     
       16. The method of  claim 10 , further including connecting a torque converter to the CVT and providing a differential for a drive output for the automobile vehicle. 
     
     
       17. A method of selecting a transmission manual mode entry gear during transient driving conditions of an automobile vehicle, comprising:
 shifting a PRNDL shift device to a Manual position to shift a continuously variable transmission (CVT) to a manual mode; 
 applying an offset to a real ratio of the CVT; 
 rounding the real ratio to a bin ratio center of a bin adjacent to the real ratio in a direction of a shift; 
 determining if a calculated entry ratio will cause the shift to pass a requested ratio; 
 entering the manual mode at the calculated entry ratio if the calculated entry ratio will not cause the shift to pass the requested ratio; and 
 entering the manual mode at a desired ratio if the calculated entry ratio will cause the shift to pass the desired ratio. 
 
     
     
       18. The method of  claim 17 , further including:
 retrieving the offset from a lookup table saved in a memory; and 
 basing the offset on a rate of real ratio change.